Austrian Utility Installs Wide Area Monitoring System

8/10/2019 Austrian Utility Installs Wide Area Monitoring System

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Austrian Utility Installs Wide Area Monitoring System

Dec 18, 2006 11:12 PM

Austria is the latest country to monitor the stability of its power transmission networkwith an ABB wide area monitoring system (WAMS), an advanced early warning

technology for power grids that helps operators prevent system instabilities andoverloads, as well as cascade tripping that leads to power blackouts

WAMS technology solves one of the power industry!s most pressing problems" how toensure grid reliability by detecting and counteracting the first signs of grid instability #heAustrian utility, $erbund%Austrian &ower 'rid (A&'), installed a new monitoring systemfrom ABB to complement three recently commissioned phase%shifting transformers thattogether optimie transmission over main power corridors

Since the spring of **+, ABB!s &S'uard -* WAMS has overseen the power flow along acrucial and heavily loaded transmission corridor between the cities of $ienna and #ernit,connecting northeastern and southern Austria

#he corridor is operated by A&', which controls a power network consisting of about -*switching and substations, and +-** km of lines

#he problem is this . much of the /0** MW of surplus power produced in northeasternAustria is transferred to the south of the country, where there is a deficit of /1** MW #omeet the heavy demand for power in the south, surplus electricity is transmitted overthree * k$ power lines that have a total capacity of /** MW

2ncreased congestion restricts the flow of electricity andthreatens the security of supply 3ompounding thecongestion is the gradual addition of another /*** MW

of electricity from wind generation in the northeast, aswell as the closure of coal%fired power plants in thesouth, which is creating even greater demand for powerfrom the north

#he solution that stabilies and protects the corridor isan intelligent combination of ABB!s &S'uard monitoring

system with phasor measurement units (&M4s) and three phase%shifting transformersinstalled at critical nodes in the network

#hese ABB transformers in three of A&'5s substations protect the power lines byregulating the power flow and by preventing the loss of lines through physicaloverloading

Since the spring, &S'uard has monitored loading of the * k$ double lines, and in thefuture will also coordinate the operation of all three phase%shifting transformers forma6imum performance 7ine over% and underloads can be balanced, and losses causedby uncoordinated loop flows (inadvertent power losses as electricity is transmittedthrough the network) can also be minimied

With these technologies, A&' can get the most use out of its e6isting transmissioncapacities, and at the same time significantly reduce the risk of a blackout caused byoverloaded lines At the beginning of 8ecember **+, all three transformers and themonitoring system were 9ointly and successfully commissioned An additional order for

the integration of the &S'uard system with the network control system has already beenawarded by A&'

With ABB5s &S'uard WAMS, operators canmonitor their power network very precisely

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Satellite-synchronized measurements

Austrian &ower 'rid!s &S'uard employs applications like phase angle monitoring (&AM),which scrutinies network stresses caused by heavily loaded lines, and line thermalmonitoring (7#M), which determines average line temperature and temperature changes

Measurements are taken with ABB &M4s . measuring devices that are installed at criticalnodes in the power network and use a '&S satellite signal to time%synchronie voltageand current readings as they are taken from their points of origin

8ata can be streamed into a control center from far%flung points in the grid, where it isevaluated to give grid operators a precise picture of what is happening in their system,online #hey can also finally see what is happening beyond their own control area . anadvance over traditional monitoring and protection methods

An effective solution

2t means they can react swiftly and effectively when confronted with sudden interruptionsor bottlenecks in the power flow, and win time to prevent the spread of disturbances thatcan potentially bring down the entire network

:#he information, especially on the load flow and average temperature progression on thedouble lines will aid our operational staff in fully utiliing their transmission capacity andmaintaining integrity at the same time,; said M) system that is under development in a test operation#he &>M makes it possible to detect the e6citation of one of the two ma9or interareaoscillation modes that e6ist in the 43#= power system

At the end of ?anuary **+, for e6ample, schedule changes e6ceeding - 'W betweenindividual systems were noted #hese power changes resulted in fre@uency deviations ofmore than */-


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for the creation of a detailed system overview Also, post processing of these signalsopens the door to a new dimension of wide%area system control and protection

#his is in stark contrast to previous methods of power system monitoring, which wasperformed with S3A8A systems that deliver measurements or estimated values in -% to*%second intervals A steady%state snapshot of the transmission system gives anoverview of topology, power flows, voltage profiles and power%fre@uency controlleroperation #he information displayed covers the complete national operation area andonly partial sections of the neighboring systems

#he use of WAM measurements enables system dynamic behavior to be permanentlymonitored and, when coupled with smart computations algorithms, an early%warningsystem against dangerous system operation is established #his practice started in **in Switerland, which occupies a strategic position in the 43#=, and is now the sub9ect ofthe latest system and functionality e6pansion

#$!!ID$! M$NI"$!ING

Switerland has a power%transfer load through the Swiss transmission system that ise@uivalent in magnitude to the system load itself #hus, corridor monitoring is a veryimportant task &hase measurement units (&M4s) enable the e6act measurement ofvoltage phase difference along the corridor Based on only two measurements, thesystem loading and the complete topology between the two substations can bemonitored igure shows the complete signal chain from the feeder up to the S3A8Asystem

8ata communication between the substation and the data concentrator consists only ofpositive se@uence phasor values for current, voltage and the determined fre@uency =achmeasurement package has an individual time stamp or the communication itself,standardied protocols are used #he ac@uired data are stored in an >&3 database with atime resolution of /** msec

8edicated information is piped from the data concentrator to the control room #hisinformation consists of either alarms or other calculated values from the differentpermanent running applications #he main challenge is to e6tract important informationfrom analying electromechanical dynamics of the whole system and send correspondingalarms to the control%room operators 2n addition, the planning departments couldbenefit from calibrating their dynamic models on e6ports of synchronied high%resolutionmeasurements on different feeders

#he impact of events far from the well%monitored system is shown in ig 2n the eventof losing a section of the transmission system during the 2talian import of severalthousand megawatts through the systems of Slovenia, Switerland and rance, anautomatic higher loading of the rest of the interconnection lines will occur 2n thisparticular mode of operation, more than an additional -** MW will flow through the Swisssystem on the four main *%k$ north%south transmission lines #his additional load flow,about /** MW for each line, correlates with a stepwise increase of the voltage phase%angle difference from the northern to the southern system border of - degrees

S"A%I&I"' M$NI"$!ING

#he highly interconnected 43#= power system has reached a critical sie &oorly dampedinterarea oscillations recorded in **- have shown that dynamic system behavior has tobe carefully observed to prevent unfavorable system situations #herefore, themeasurements available from the Swiss data concentrator were used for the e6traction ofdynamic system information together with many other recordings on the complete 43#=power system igure 1 gives an overview of the current synchronous interconnected

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system and the location of the on%line connected &M4s or Switerland, these arepositioned in Bassecourt Substation on the northwest border, Mettlen Substation in thecenter of the transmission system, and 7avorgo, Soaa and Cobbia substations on thesouthern border Based on bilateral agreements with =7=S (Slovenia) and ('reece),two other substations at 8ivaca and Ag Stanfos are e@uipped to complete the system

#he first successful application of the on%line dynamic system monitoring was performedduring the critical phase of the resynchroniation of the first and second 43#= ones on>ct /*, **1 At that time, a permanent modem link from Dagreb (3roatia) to7aufenburg (Switerland) enabled the resynchroniation team to be sure that, during theweak interconnection time window, no instabilities occurred

M can detect the e6citation of one of the twoma9or interarea oscillation modes e6istent in the 43#= power system #he most visible isthe east%west mode reflected by active power swings in the east%west direction that canbe measured on the tie lines connecting areas on this a6is or the fre@uency at the=astern system margin As input for recording this mode, the comparison between thefre@uency in Switerland and 'reece is used Similar results can be obtained by using thevoltage phase%angle difference between 'reece and Switerland #he second mode,which reflects the north%south interarea oscillation, is also monitored by swissgrid ag byusing, as input, the active power flows of two *%k$ tie lines oriented in the north%southdirection as part of the import corridor from the Forth to 2taly

#he timely high%resolution measurements (every /** msec is one measurement set) aresubse@uently processed in such a way that as a result of an on%line parameter estimationtogether with a modal analysis, three main parameters describing the system dampingare calculated and stored in the measurement database" damping factor, oscillationamplitude and oscillation fre@uency #he most recent interarea oscillation observed in the43#= power system is shown in ig + and the corresponding oscillation monitoring tooloutput is presented in ig G

By using both indices, namely the damping factor and the oscillation amplitude, togetherwith a timer allows creation of a reliable oscillation alarm, which triggers ac@uiringadditional recordings or for performing system topology improvements 3urrently, thissignal is used only for monitoring purposes, but in the future it may be integrated inspecial protection schemes or enhanced control loops

") $U"&$$*

Capid and fre@uent changes of power%flow patterns have to be managed by transmissionsystem operators with the help of enhanced system monitoring tools >ne possiblesolution is a WAM approach in order to enable control%room operators to react faster Adedicated aggregation of global information of the system creates intelligent alarmscontaining comprehensive information related to highly meshed systems Based on post%

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processing of measurements, coordinated actions can be initiated in order to preventcascaded events

3urrent developments in data ac@uisition, reliable and fast telecommunication systemscombined with increased computation power enables power engineers to implement newcomprehensive monitoring and control schemes, which increase power system securitywith faster reaction


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"he %ul (ower Grid Sees Intelligent $,eration

&an 2, 2007 ':'1 PMby Ric( Bu$", )ditorial Director, and *ene Wol, +ontributing )ditor

Much of the developed world!s transmission grid is approaching the end of its design life

and is sub9ect to headline%grabbing failures At the same time, the industry!s technicalworkforce is poised for retirement #hese people built, operated and maintained thelargest and most comple6 machine the world has yet to see Cegrettably, they will takewith them intimate knowledge of e6actly how it operates Because so many utilities haveunderinvested in any type of succession plan, there is a loss in situational awareness ofthe power grid system 3ombine this with the increasing demand for power, changingregulation and increasingly comple6 interconnections, and the stage has been set formore and bigger blackouts

ortunately, the development of technology that could automate, manipulate and monitorbasic e@uipment, such as switches, capacitors and relays, began in the late /0*s #histechnology is reaching the stage of deployment at a time when it will be a ma9or player inthe solution

#he technology is a highly intelligent combination of high%speedcommunications, information technology and process competency #ogether, it forms afast and reliable decision%making system to predict, prevent and mitigate disturbances

(hasor Monitoring

Many years ago, Bonneville &ower Authority (B&A) developed a monitoring system calledthe phasor measurement unit (&M4) 2t monitors voltage and current phase angles,which can be used to predict developing instability 2nitially, the Western =lectric3oordinating 3ouncil (W=33) and =&C2 deployed the &M4 as a real%time wide%area

monitoring system (WAMS) with / &M4s at si6 utilities 7ast year, there were +* &M4sinstalled on eight utility systems with phasor data concentrators at control centersbelonging to W=33 members

3hina started deploying WAMSs in ** 8r 3hristian Cehtan, ABB 3hina vice presidentand director of corporate research, says that 3hina is currently doing some of the mostadvanced work in this field developing applications to interpret basic &M4 data #oday,3hina has installed /* central computers with ** to ** &M4s in five regional and fiveprovincial power systems According to Cehtan, the challenge facing researchers is todevelop methods to analye the millions of data points from the WAMS #he =astern2nterconnection &hasor &ro9ect (=2&&) is another &M4 system that has deployed about G-&M4s =2&& is a 8epartment of =nergy (8>=) and 3onsortium for =lectric Celiability

#echnology Solutions (3=C#S) initiative that started in >ctober **

"he .//0 1lacout

#he August ** blackout affected /* million people in 3anada and 1* million people innortheastern 4nited States >utage%related financial losses were estimated atappro6imately 4S+ billion

Cobert 3ummings, director of events analysis and information e6change for the ForthAmerican =lectric Celiability 3ouncil (F=C3), reviewed some &M4s and other data from

9ust prior to and during the August ** outage Bus fre@uencies showed a fluctuation,and phase angles seen in >hio and Michigan began to diverge from each other hours

before the outage


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Sta1ility Management

>ne problem facing transmission system operators is system stability &ower transferscould be increased if stability was not a limiting condition &symetri6 7td has developedan oscillatory stability management system called the StormMinder 8r 8ouglas Wilsonsays that the StormMinder system uses a technology that monitors the smallperturbations that are always on the power system #he operator is provided with real%time displays and alarms for system damping According to Wilson, &symetri6 hasinstalled its system on the Australian network 2n **1, the StormMinder systemidentified severe oscillations and their locations on the Australia network Becauseoperators were able to use this information, a serious blackout was prevented #he&symetri6 system has also been installed in Manitoba, 3anada

After some serious power interruptions in =urope and Forth America, AC=$A #K8 Eworking with a group of utilities (American =lectric &ower NA=&O, Fortheast 4tilities,Ameren, #$A, =ntergy and irst =nergy) E developed a software system called e%terrai$ion to help system operators anticipate and avoid problems that could lead tobrownouts and blackouts #he software is a decision%support system for the control

center 2t takes the accumulation of real%time data from supervisory control and dataac@uisition systems, energy management systems and WAMS, giving the operator avisualiation of the systems, talk about being user friendly #he operator can developdynamic dashboard displays, on the fly, of e6actly the type of information needed for theconditions #hey have the vital signs of the systems at their fingertips 2n effect, e%terrai$ion is a platform and methodology to develop applications that enhancesituational awareness in the control center

AC=$A #K8 and its utility partners continued to ask :what if; in the development of e%terrai$ion and have outlined the basics for an e%terra suite Why not have variousdecision%making capabilities built into the real%time visualiation softwareP #he suitecombines elements of a browser for monitoring the grid behavior, an archive to store and

analye historical information, a modeler for energy management, a securityenvironment for cyber protection, a centralied alarm management system, andsubstation automation to monitor, control and protect system operation

Su1station Intelligence

Series capacitors are another way to increase the power flow down a transmission line,but they have some problems associated with them As compensation levels areincreased, subsynchronous resonance (SSC) and possible damage to generationresources become a problem Add some intelligent power electronics in the form ofthyristor controls, and the system operator doesn!t have to monitor for SSC in addition tothe other system properties SSC has gone away Some call the thyristor%controlled

series capacitor a :stealth; capacitor

B&A, =&C2 and '= =nergy pioneered this technology in the early /00*s with the SlattSubstation thyristor%controlled series capacitor installation where, like capacitors,transformers, breakers, switches and other substation devices are not consideredintelligent by themselves But add monitors and the switchyard becomes smart #oday,however, there is a wide selection of intelligent electronic devices (2=8s) available foralmost every piece of substation e@uipment Southern States, 773 has developed acurrent monitoring device that clamps on stands below the substation bus 2t useselectromagnetic fields to sense voltage and current levels without being physically placedin the circuit, making it handy to monitor in e6tremely tight spaces ABB, '= =nergy,AC=$A and Siemens have developed systems to replace the labor%intensive station

checks with real%time monitoring of station e@uipment and circuits

"ransformers can 1e smarter

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#he typical large power transformer is a million to - million investment for a 4Sutility, and replacing it takes about two to three years Qet few utilities have real%timemonitoring systems installed on these critical pieces of e@uipment 2t isn!t e6pensive toinstall, and transformer%monitoring e@uipment offers new advances in its data%collectionabilities Ceal%time monitoring of oil for gas chromatography is available, as istemperature detection for hot spots, oil temperatures, load tap changer temperatures

and cooling efficiencies

#he real trick is converting the data into usable information #his information is importantto utilities because it allows them to schedule work based on the condition of thee@uipment rather than basing maintenance on the calendar #he system operator canload transformers and receive real%time feedback about the actual condition of thetransformer rather than an operating procedure based on conservative guesswork by anengineer sitting miles away from the actual unit

'= =nergy, SiemensHServeron, ABB, Morgan Shaffer, 8ynamic Catings and Schweiterare a few of the manufacturers developing complete monitoring systems to giveoperations and maintenance personnel a real understanding of how the e@uipment in the

substation is performing and the true conditions under which they are operating

(ower lectronics

>nce the intelligence is in place to investigate loop flows, as well as resonance and low%fre@uency oscillations, tools are needed to counteract that instability >therwise, utilitiesare reduced to tripping generation and shedding load le6ible A3 #ransmission System(A3#S), partially funded by =&C2 and developed by '= =nergy, Siemens, ABB, Mitsubishiand AC=$A, meets these re@uirements with devices that make it possible to counteractelectrical disturbances before they impact the end user, such as the phenomenon ofvoltage fluctuations, flicker and voltage sags =6amples include"

Su#er -.R/ 8eveloped by #ennessee $alley Authority (#$A) and AmericanSuperconductor 3orp, this high%temperature superconducting synchronouscondenser corrects voltage sag immediately 2t is rated at /* M$AC #he firstSuper $AC went into service in **- on the #$A system Since then, #$A haspurchased five of the units

S-+ lig"t/ ABB has developed a S#A#3>M device (static compensator) usingvoltage%source converter technology and insulated gate bipolar transistortechnology to control reactive power

.danced #"a$e$"iting tran$or!er/ '= =nergy developed the $ariablere@uency #ransformer ($#), a continuous phase%shifting transformer based onrotating machine technology 2t also has one power grid connected to the rotorand the other grid to the stator 2n effect, it is a rotating machine that operateslike a converter station, connecting two asynchronous systems without the hassleof a converter station #here are no harmonic filters and the control system usesprogrammable logic controllers based on ladder logic 2t can be replaced easilywhen control technology needs to be upgraded, making it a true plug%and%playdevice relying on tested technology packaged for the /stcentury #he first $#was installed on the


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technology can transform it into an intelligent power system #he intelligent bulktransmission grid is an ambitious undertaking whose time has come

Increasing Grid #a,acity with Su,erconducting #a1le

Austrian Utility Installs Wide Area Monitoring System

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